I am living with my father in laws house since 20 years, My wife was adopted from the brother of my

I am living with my father in laws house since 20 years, My wife was adopted from the brother of my mother in law. She was not legally adopted ,she was adopted at the age of 6 months. We got married and after 4 years of marriage my Father in law got an Heart attack so i have to stay with them as they had not any son to look after him. My mother in law expired in 2014. After her death my father in law had wrote a will in the name of my wife. but now He is willing to give the property to his brother's son. My father is 87 yrs old. Can he give property to his nephew?